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MAC LAYER PROTOCOLS
successful. An overhearing station, which might have received RTS and
DS but not CTS, defers its transmissions until after the ACK frame
should have been received plus a random time.
To sum up, a successful data transfer (A to B) consists of the fol-
lowing sequence of frames:
1. “Request to send” (RTS) frame from A to B
2. “Clear to send” (CTS) frame from B to A
3. “Data sending” (DS) frame from A to B
4. DATA fragment frame from A to B
5. Acknowledgment (ACK) frame from B to A
MACAW is a nonpersistent slotted protocol, meaning that after
the medium has been busy—for example, after a CTS message—the
station waits a random time after the start of a time slot before send-
ing an RTS. is results in fair access to the med ...